/*******************************************************************************
 * 	Copyright 2016 ContainX and OpenStack4j                                          
 * 	                                                                                 
 * 	Licensed under the Apache License, Version 2.0 (the "License"); you may not      
 * 	use this file except in compliance with the License. You may obtain a copy of    
 * 	the License at                                                                   
 * 	                                                                                 
 * 	    http://www.apache.org/licenses/LICENSE-2.0                                   
 * 	                                                                                 
 * 	Unless required by applicable law or agreed to in writing, software              
 * 	distributed under the License is distributed on an "AS IS" BASIS, WITHOUT        
 * 	WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the         
 * 	License for the specific language governing permissions and limitations under    
 * 	the License.                                                                     
 *******************************************************************************/
package com.huawei.openstack4j.openstack.common;

import java.util.Collections;
import java.util.List;

import com.fasterxml.jackson.annotation.JsonIgnore;
import com.huawei.openstack4j.core.transport.ListType;
import com.huawei.openstack4j.model.ModelEntity;

/**
 * A List result which wrappers a JSON Array
 *
 * @param <T> the generic type
 */
public abstract class ListResult<T> implements ModelEntity, ListType {

	private static final long serialVersionUID = 1L;

	protected abstract List<T> value();
	
	@JsonIgnore
	public List<T> getList() {
		if (value() == null)
			return Collections.emptyList();
		return value();
	}

	
    public T first() {
    	return value().isEmpty() ? null : value().get(0);   	
    }
}
